A novel virus is a virus that has not previously been recorded. It can be a virus that is isolated from its natural reservoir or isolated as the result of spread to an animal or human host where the virus had not been identified before. It can be an emergent virus, one that represents a new virus, but it can also be an extant virus that has not been previously identified.
Coronaviruses are a group of related RNA viruses that cause diseases in mammals and birds. In humans and birds, they cause respiratory tract infections that can range from mild to lethal. Mild illnesses in humans include some cases of the common cold, while more lethal varieties can cause SARS, MERS, and COVID-19. In cows and pigs they cause diarrhea, while in mice they cause hepatitis and encephalomyelitis.
Severe acute respiratory syndrome–related coronavirus is a species of virus consisting of many known strains phylogenetically related to severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) that have been shown to possess the capability to infect humans, bats, and certain other mammals. These enveloped, positive-sense single-stranded RNA viruses enter host cells by binding to the angiotensin-converting enzyme 2 (ACE2) receptor. The SARSr-CoV species is a member of the genus Betacoronavirus and of the subgenus Sarbecovirus.
Severe acute respiratory syndrome coronavirus 1 is a strain of coronavirus that causes severe acute respiratory syndrome (SARS), the respiratory illness responsible for the 2002–2004 SARS outbreak. It is an enveloped, positive-sense, single-stranded RNA virus which infects the epithelial cells within the lungs. The virus enters the host cell by binding to angiotensin-converting enzyme 2. It infects humans, bats, and palm civets.
Canine coronavirus (CCoV) is an enveloped, positive-sense, single-stranded RNA virus which is a member of the species Alphacoronavirus 1. It causes a highly contagious intestinal disease worldwide in dogs. The infecting virus enters its host cell by binding to the APN receptor. It was discovered in 1971 in Germany during an outbreak in sentry dogs. The virus is a member of the genus Alphacoronavirus and subgenus Tegacovirus.
An emergent virus is a virus that is either newly appeared, notably increasing in incidence/geographic range or has the potential to increase in the near future. Emergent viruses are a leading cause of emerging infectious diseases and raise public health challenges globally, given their potential to cause outbreaks of disease which can lead to epidemics and pandemics. As well as causing disease, emergent viruses can also have severe economic implications. Recent examples include the SARS-related coronaviruses, which have caused the 2002-2004 outbreak of SARS (SARS-CoV-1) and the 2019–21 pandemic of COVID-19 (SARS-CoV-2). Other examples include the human immunodeficiency virus which causes HIV/AIDS; the viruses responsible for Ebola; the H5N1 influenza virus responsible for avian flu; and H1N1/09, which caused the 2009 swine flu pandemic. Viral emergence in humans is often a consequence of zoonosis, which involves a cross-species jump of a viral disease into humans from other animals. As zoonotic viruses exist in animal reservoirs, they are much more difficult to eradicate and can therefore establish persistent infections in human populations.
Middle East respiratory syndrome–related coronavirus (MERS-CoV), or EMC/2012 (HCoV-EMC/2012), is the virus that causes Middle East respiratory syndrome (MERS). It is a species of coronavirus which infects humans, bats, and camels. The infecting virus is an enveloped, positive-sense, single-stranded RNA virus which enters its host cell by binding to the DPP4 receptor. The species is a member of the genus Betacoronavirus and subgenus Merbecovirus.
Novel coronavirus (nCoV) is a provisional name given to coronaviruses of medical significance before a permanent name is decided upon. Although coronaviruses are endemic in humans and infections normally mild, such as the common cold, cross-species transmission has produced some unusually virulent strains which can cause viral pneumonia and in serious cases even acute respiratory distress syndrome and death.
Middle East respiratory syndrome (MERS), also known as camel flu, is a viral respiratory infection caused by Middle East respiratory syndrome–related coronavirus (MERS-CoV). Symptoms may range from none, to mild, to severe. Typical symptoms include fever, cough, diarrhea, and shortness of breath. The disease is typically more severe in those with other health problems.
Pipistrellus bat coronavirus HKU5 is an enveloped, positive-sense single-stranded RNA mammalian Group 2 Betacoronavirus discovered in Japanese Pipistrellus in Hong Kong. This strain of coronavirus is closely related to the newly identified novel MERS-CoV that is responsible for the 2012 Middle East respiratory syndrome-related coronavirus outbreaks in Saudi Arabia, Jordan, United Arab Emirates, the United Kingdom, France, and Italy.
Human coronavirus HKU1 (HCoV-HKU1) is a species of coronavirus in humans. It causes an upper respiratory disease with symptoms of the common cold, but can advance to pneumonia and bronchiolitis. It was first discovered in January 2004 from one man in Hong Kong. Subsequent research revealed it has global distribution and earlier genesis.
Human coronavirus 229E (HCoV-229E) is a species of coronavirus which infects humans and bats. It is an enveloped, positive-sense, single-stranded RNA virus which enters its host cell by binding to the APN receptor. Along with Human coronavirus OC43, it is one of the viruses responsible for the common cold. HCoV-229E is a member of the genus Alphacoronavirus and subgenus Duvinacovirus.
Tylonycteris bat coronavirus HKU4 is an enveloped, positive-sense single-stranded RNA virus mammalian Group 2 Betacoronavirus that has been found to be genetically related to the Middle East respiratory syndrome-related coronavirus (MERS-CoV) that is responsible for the 2012 Middle East respiratory syndrome coronavirus outbreak in Saudi Arabia, Jordan, United Arab Emirates, the United Kingdom, France, and Italy.
Miniopterus bat coronavirus 1 is a novel enveloped, single-stranded positive-sense RNA virus species in the Alphacoronavirus, or Group 1, genus with a corona-like morphology. It causes severe acute respiratory syndrome in bats. Isolates have not been found in humans.
MERS coronavirus EMC/2012 is a strain of coronavirus isolated from the sputum of the first person to become infected with what was later named Middle East respiratory syndrome–related coronavirus (MERS-CoV), a virus that causes Middle East respiratory syndrome (MERS).
London1_novel CoV/2012 is a coronavirus strain isolated from a Qatari man in London in 2012 who was one of the first patients to come down with what has since been named Middle East respiratory syndrome-related coronavirus (MERS-CoV). The Qatari patient had traveled to Saudi Arabia from Qatar. He returned to Qatar, but when he fell ill, he traveled to London for treatment. The United Kingdom's Health Protection Agency (HPA) named the virus.
Bat virome refers to the group of viruses associated with bats. Bats host a diverse array of viruses, including all seven types described by the Baltimore classification system: (I) double-stranded DNA viruses; (II) single-stranded DNA viruses; (III) double-stranded RNA viruses; (IV) positive-sense single-stranded RNA viruses; (V) negative-sense single-stranded RNA viruses; (VI) positive-sense single-stranded RNA viruses that replicate through a DNA intermediate; and (VII) double-stranded DNA viruses that replicate through a single-stranded RNA intermediate. The greatest share of bat-associated viruses identified as of 2020 are of type IV, in the family Coronaviridae.
Since 2012, an outbreak of Middle East respiratory syndrome coronavirus has affected several countries, primarily in its namesake, the Middle East. The virus, which causes Middle East respiratory syndrome (MERS), is a novel coronavirus that was first identified in a patient from Jeddah, Saudi Arabia on June 6, 2012.
Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) is the virus that causes COVID-19, the respiratory illness responsible for the COVID-19 pandemic. Also colloquially known simply as the coronavirus, it was previously referred to by its provisional name, 2019 novel coronavirus (2019-nCoV), and has also been called human coronavirus 2019. First identified in the city of Wuhan, Hubei, China, the World Health Organization declared the outbreak a Public Health Emergency of International Concern on 30 January 2020, and a pandemic on 11 March 2020. SARS‑CoV‑2 is a positive-sense single-stranded RNA virus that is contagious in humans. As described by the US National Institutes of Health, it is the successor to SARS-CoV-1, the virus that caused the 2002–2004 SARS outbreak.
This article documents the chronology and epidemiology of SARS-CoV-2 in January 2020, the virus which causes the coronavirus disease 2019 (COVID-19) and is responsible for the COVID-19 pandemic. The first human cases of COVID-19 were identified in Wuhan, China, in December 2019.
The history of coronaviruses is a reflection of the discovery of the diseases caused by coronaviruses and identification of the viruses. It starts with the first report of a new type of upper-respiratory tract disease among chickens in North Dakota, U.S., in 1931. The causative agent was identified as a virus in 1933. By 1936, the disease and the virus were recognised as unique from other viral disease. They became known as infectious bronchitis virus (IBV), but later officially renamed as Avian coronavirus.